Cavelord

A 2D side-scrolling shooter where you must explore caves to find the three pieces of the crown for the king. The large playfield is notable for an enormous amount of movement, with flowing water and swaying vines. Hidden triggers will cause explosions or lightning bolts to strike that will injure the player, as well as falling stones, and two dreaded birds that keep spawning to harass you. The player looks like they are riding on a stork and have a lance, similar to the characters in Joust, though the translated story says you are on a winged horse.

Though the game is short, it is known for being very difficult. It has three difficulty levels, named slightly different depending on translation, corresponding to easy, medium and hard, which controls how regularly the explosions and lightning bolts go off, as well as the speed the birds spawn and move.

The game was released in Germany, but Wikipedia offers a rough translation of the story in the game: The player controls the hero Telos on his winged horse Pegamis and has to explore two caves within a large scrolling playfield. While exploring the caves the player is threatened by flying creatures called "Nemesides" that appear occasionally.